Same discusssion was going on at this thread : Re: How to Integrate Webcenter and MS Sharepoint
So are you looking for the content migration from MS sharepoint to webcenter (portal/content) or you are intented to use ECM as content repository and Webcenter portal as portal (UI) ?
If you only concern about content migration then lot of valuable info you will get from the below links -
and even connectors's are avaliable -
The satisfactory answer will depend on the complexity of the existing systems and the targeted (new webcenter portal's) portals complexity.
Hope you can get some thought over it.
i'm coming from microsoft sharepoint world to oracle webcenter...! i know both of them are portal collaboration softwares. But here the challenge is i should now understand the webcenter architecture and want to quickly move on to develop some custom plug and play components. i need guidance in this regard.